Liquid detergents based on anionic surfactants mixed with non-ionic surfactants are used for the domestic washing of clothes.
Co-pending PCT/EP2014/069565 (C4800) and PCT/EP2015/050239 (C4802) disclose blue or violet dye polymer, comprising a polyethylene imine covalently bound to a reactive dye, the polyethylene imine having from 6 to 1000000 nitrogen atoms, wherein from 20 to 95 mol %, of the totality of the protons of the primary and secondary amine nitrogen atoms of the unsubstituted polyethylene imine are substituted by iso-propyl alcohol or ethyl alcohol groups. Such dye polymers deposits to polyester and cotton clothes under wash conditions and thereby whitening the fabric via a shading effect.
Liquid detergent formulations containing Alkyl Ether Sulphate surfactant are widely used for the domestic washing of clothes.
Cotton clothes can undergoing greater yellowing than polyester, under such conditions it would be desirous to have greater relative deposition of the dye polymer to cotton than polyester fibres to enhance the whiteness.